The present invention relates generally to a heat exchanger and a method of forming the heat exchanger, and particularly, a multi-fluid heat exchanger.
It has become increasingly desirable for heat exchangers to exhibit efficient transfer of heat, while remaining relatively easy to make. In the automotive industry, in particular, it has become increasingly necessary to combine multiple functions in a single heat exchanger assembly. In particular, the need to reduce the number of overall components, and to optimize assembly efficiency has driven the need for improved heat exchanger devices that combine increasingly efficient designs and multiple functions in packaging heretofore attainable using plural separate components or devices having inefficient designs. More specifically, there has been a growing need for an improved heat exchanger device, particularly for under the hood automotive vehicle applications, which combines multiple functions in a single assembly that is efficient to make and operate and that occupies substantially the same or less space than existing heat exchanger devices.
Particularly in extreme operating conditions and where a multi-fluid heat exchanger is to be employed, it is also attractive to be able to selectively manage heat exchange between the different fluids, especially when the different fluids passed through the heat exchanger have substantially different flow characteristics.
The present invention meets the above needs by providing an improved heat exchanger comprising a first end tank; a second end tank opposite the first end tank; a plurality of first tubes in fluid communication with the first and second end tanks, the plurality of first tubes adapted to have a first fluid flow there-through; a plurality of second tubes in fluid communication with the first and second end tanks, the plurality of second tubes adapted to have a second fluid, different from the first fluid, flow there-through; and a plurality of fins disposed between the first and second tubes, with the first and second tubes and the fins being generally co-planar relative to each other.
In another aspect the present invention is directed to a heat exchanger comprising a first end tank; a second end tank opposite the first end tank; a plurality of first extruded metal tubes in fluid communication with the first and second end tanks, and being adapted to have a first fluid flow there-through; a plurality of second extruded metal tubes in fluid communication with the first and second end tanks, and being adapted to have a second fluid, different from the first fluid, flow there-through; and a plurality of fins disposed between the first and second tubes, with the first and second tubes and the fins being generally co-planar relative to each other; wherein at least one of the first or second extruded metal tubes includes an interior wall structure including a partition adapted for subdividing the tube into a plurality of passageways within the tube.
In yet another aspect of the present invention, there is contemplated an improved heat exchanger, comprising a first end tank; a second end tank opposite the first end tank; a plurality of first tubes in fluid communication with the first and second end tanks, the plurality of first tubes adapted to have a first fluid flow there-through, and including a first end tube defining one end of the heat exchanger; a plurality of second tubes in fluid communication with the first and second end tanks, the plurality of second tubes adapted to have a first fluid flow there-through, and including a second end tube defining one end of the heat exchanger; and a plurality of fins disposed between the first and second tubes, with the first and second tubes and the fins being generally co-planar relative to each other; wherein the heat exchanger includes no more than one end plate.
In yet another aspect of the present invention, there is contemplated a heat exchanger comprising at least one end tank divided into a first portion and a second portion by a baffle; a plurality of first tubes having a plurality of arcuate edges, in fluid communication with the first portion of the end tank, and adapted for having a first fluid flow there-through; a plurality of second tubes each having a plurality of arcuate edges, in fluid communication with the second portion of the end tank, and adapted for having a second fluid flow there-through; and a plurality of fins disposed between the first and second tubes and including a plurality of projections for opposing the pluralities of arcuate edges of the tubes and providing stability of the tubes relative to the fins during assembly.
In one particularly preferred embodiment, the present invention contemplates a heat exchanger for an automotive vehicle, comprising at least one end tank; and at least two heat exchangers including a plurality of spaced apart extruded metal tubes with fins between the spaced tubes; the heat exchangers being disposed so that their respective tubes and fins are generally co-planar with each other and are connected to the end tank; and the heat exchangers being selected from the group consisting of a transmission oil heat exchanger, a power steering oil heat exchanger, a condenser or combinations thereof.
Another highly preferred embodiment a ratio of the length to the hydraulic diameter of heat exchanger tubes in at least one of the heat exchangers is between about 80 and about 1820 and more preferably about 300 and about 700. For example, the length of tubes can be between about 200 mm to about 1000 and the hydraulic diameter is between about 0.55 to about 2.50 mm.
In yet another preferred embodiment, the invention is directed to an improved heat exchanger assembly, comprising a first heat exchanger; a second heat exchanger in generally co-planar relationship with the first heat exchanger; at least one end tank divided into an inlet portion and an outlet portion for the first heat exchanger, and being connected in fluid communication to both the first heat exchanger and the second heat exchanger; an inlet in fluid communication with the inlet portion of the first end tank; an outlet in fluid communication with the outlet portion of the first end tank; a plurality of heat exchanger tubes adapted for fluid flow therethrough in a first flow circuit, at least one of the plurality of tubes in fluid communication with the inlet portion and a least one other of the plurality of tubes in fluid communication with the outlet portion; and a bypass element located on the exterior of the end tank and being adapted for providing a passageway at an intermediate location within the first flow circuit adapted for, at relatively low operating temperatures, intercepting a fluid in the first flow circuit to divert the fluid so that it avoids passing through the entire first flow circuit.
In still another preferred embodiment, the bypass element is located external of the end tank and is particularly adapted for providing a passageway at an intermediate location within the first flow circuit adapted for inducing a first pressure gradient, at relatively low operating temperatures, and intercepting a fluid in the first flow circuit to divert the fluid so that it avoids passing through the entire first flow circuit. Thus, one preferred structure for a bypass element herein includes a first passageway that is part of the inlet, a second passageway that is part of the outlet, and a third passageway joining the first passageway and the second passageway.